1. Field of the Invention
The invention concerns a mobile concrete pump with a structural frame mounted on the undercarriage of a truck chassis, supportable upon the ground with lifting up of the truck undercarriage, with a boom stand provided on the structural frame and rotatable about a vertical axis and a concrete distribution boom in the form of a multi-member articulated boom including a first boom arm pivotable at a first articulation linkage about a horizontal articulation axis relative to the boom stand and additional boom arms pivotable relative to each other at articulation linkages about the horizontal articulation axis.
2. Related Art of the Invention
Concrete pumps of this type receive concrete brought in to construction sites by transport vehicles, and convey the concrete via the distribution boom to a site in need of concrete. Conventionally the concrete pumps are mounted upon multi-axis vehicle chassis with continuous, rigid structural frames. For heavy vehicles with a total weight of greater than 24 tons multi-axle heavy duty chassis with high axle loads are necessary. These are allowed to travel upon public roads only with special permission and are not allowed to use many lightly paved roads and bridges. Further, in a self-propelled concrete pump of the above described type, it is known (EP-B-0038954) to use the semi-trailer of a tractor trailer rig as a structural frame for the concrete pump and the distribution boom. Therewith, while maintaining the prescribed weight limits, the total tractor trailer can achieve an increase in the reach of the distribution boom, and can do this without compromise or loss in stability despite the comparatively light weight construction of the semi trailer. This was accomplished in that the tractor trailer rig is lifted from the ground with its weight of approximately 7 to 9 tons used as ballast for stabilizing the distribution boom. However, here also the department of transportation regulations set a limit on the vehicle length and height, which impedes a further enlargement of the reach or range.